基于前期高龄若虫数量的褐飞虱发生量预测

Prediction on Occurrence of Brown Planthopper Based on Early Number of Nymphs

通过追踪褐飞虱不同梯度高龄若虫的田间消长动态,分析了褐飞虱四(2)代高龄若虫数量与五(3)代褐飞虱发生程度的关系。结果表明,四(2)代高龄若虫残留量(x^1)决定了五(3)代发生程度,其预测如下:x^1≤10,轻发;10<x^1≤20,偏轻;20<x^1≤50,中等;50<x^1≤100,偏重;x^1>100,大发生。该方法比依据短翅成虫进行预测预警时间较长,比依据四(2)代残虫进行预测操作简单,是褐飞虱发生量预报的一种补充手段。

The relationship between the number of nymphs from the four （2） generation and the occurrence of five （3） generation of brown planthopper was analyzed, by tracking the field dynamics of different gradients of brown planthopper. The results showed that four （2） generation of old age nymph residues（x1） determined the degree of occurrence of five （3） generation. Its prediction was as follows： 10 ≤x^1≤20, partial light; 20≤x^1≤50, medium; 50 ≤x^1≤100, emphasis; x^1〉 100, large occurrence. This method was easier to predict and forecast than the short-winged adults. It was a simple method to predict the occurrence of brown planthopper.